Electric flatiron



Sept. 30, 1952 A, GUERRA 2,612,587

ELECTRIC FLATIRON Filed March 23, 1950 EVEN/72 Ubse Arzfom'o Guerra UNITED Patented Sept. 30, 1952 ELECTRIC FLATIRONi v Jose Antonio Guerra, San Salvador, El Salvador Application March 23, 1950, Serial No. 151,400

' 2 claims. (01. 219-45) 'The present invention relates to an electric flat iron and more particularly to an electric flat'iron in which the electric current supplied to the iron heating element is more efficiently utilized. i

In conventional electric fiat irons, such as those now commercially available, an electrical resistance heating element is tightly compressed between a pair of heavy masses of metal which constitute the body of the iron and give it a requisite pressing weight. As a result, the heat developed by the heating element is transmitted and dissipated throughout the mass of the heavy metal elements. This dissipation of heat has resulted in the consumption of a relatively large amount of electric energy for a relatively small effective heat output.

The device of the present invention provides a novel type of electric flat iron in which the resistance heating element is compressed between two relatively thin plates, the lower plate being of steel or other metal having relatively good heat transfer characteristics so that it may serve as the sole or pressing plate of the iron.

The upper plate is preferably formed of metal having 9, relatively low specific heat coefiicient, preferably on the order of less than about 0.07 calories per gram at iron operating temperatures, which may attain a maximum of about 500-600 F. Suitable metals for such use are lead, platinum, silver, tin, and tungsten.

The advantages of employing such materials having low specific heat c-oefiicients will be appreciated from the fact that a much smaller heat input is necessary to raise these materials tothe temperature of the heating element, thereby preventing the loss of heat by absorption in the upper plate. Consequently, a larger proportion of the heat introduced into the heating element is available for use at the sole plate and great economy'in operation results.

v In addition, the necessary weight for effective pressing action of the iron is obtained by means of a second low specific heat member disposed out of thermal contact with either the heating element or the upper and lower plates in. contact therewith. The thermal insulation of the weight may be obtained either by the employment of thermal insulating material or by an air gap, or preferably by a combination of these insulating media. In this manner, the

distribution of the heat furnished to the heating element is confined to a relatively small portion of the iron and not to the weight mass of theiron. I

It is, therefore, an important object-ofthe present invention to provide a novel form .of an electric fiat iron which efiiciently utilizes electrical thermal energy supplied thereto.

Another important object of the present invention is to provide an electrical fiat iron including an electrical resistant heatingelement in thermal proximity to a sole plate and to a pressure plate having a low specific heat coeflicient, whereby a great proportion of the electrical thermal energy supplied to the heating element is transmitted to the sole plate with small heat loss through the pressure plate.

It is a further object of the present inven-. tion to provide an improved electric fiat iron including a heating element confined under pressure between a sole plate and a pressure plate in efficient thermal proximity and an ad-,

ditional weight in insulated thermal relation to the heating element and the pressure plate, said Weight and said pressure plate being formed of materials having low specific heat coefficients at the operating temperature of the iron to prevent the loss of thermal energy.

Still another important object of the present invention is to provide an electric flat iron comprising a heating element in efiective thermal relation to a sole plate and means having a low specific heat coeflicient for confining thermal energy from the heating element to the sole plate, thereby obtaining effective use of the heat energy supplied to the heating element.v

Other and further important objects of this invention will be apparent from the disclosures in the specification and the accompanying drawings.

On the drawings:

Figure 1 is a side elevational view, with parts broken away and in section, of an electric fiat iron of the present invention;

Figure 2 is an exploded, sectional view with parts shown in elevation of the iron in Figure 1; and

Figure 3 is a sectional view with parts shown in elevation, taken along the plane IIIIII of Figure 1.

As shown on the drawings:

As shown in Figure 1, reference numeral l0 refers generally to an electric flat iron of the present invention, including a sole plate I I having an upturned marginal flange, a pair of upstanding exteriorly threaded posts l3 secured, as by welding, to the interior surface of the sole plate I l and projecting upwardly therebeyond, a sheet metal cover i4 having its lower free end bottomed on the sole plate I I in nested relation with the flange [2 and secured to the upper end of the posts l3 by suitable means, as by a nut l5, and a handle carried by the cover 14 and secured thereto by suitable means (not shown).

Enclosed within the housing defined by the cover [4 and the sole plate H and in pressure contact with the interior surface of the sole plate H is a heating element assembly l1, including electrical resistance wires [8 wrapped or coiled about a substantially flat core plate IS. The wires I8 have suflicient resistance to permit the passage of only that current necessary to heat the sole plate H to the desired operating temperature. An insulating plate 20 is disposed on each side of the core plate I9 in contact with the resistance heating wire [8. The plates 20 are substantially coextensive in both length and breadth with the sole plate H, and each of the plates l9 and 20 is apertured, as at 2!, along its length to receive the posts [3 without physically contacting the posts. The plates2flare thus in contact with the resistancewire 18 and serve to electrically insulate the Wires from the sole plate II. The plates [9 and'20 are each madeof an effective electrical insulating material; preferably of-mica or the like. .I

Superimposed upon the heating'elementas sembly I1 is a pressure plate 22 which is 'sub-' stantially coextensive with the plate 20 and which is apertured at 23 to receive the posts 1'3 without actual physical contact therewith. The pressure plate 22 is preferably made up of a material having a low specific heat coefficien't, such as lead, tungsten, platinum, silver, or tin.

A'sheet of thermal insulating material 24, such as asbestos andthe like, is superimposed on the pressure plate 22 in surface contact therewith. Pressure is appliedito the heating element assentbly H, the pressure plate 22, and the thermal in-' sula'ting material 24 by-meansoiseparate washers 25 for each'of the posts l3-and a nut 26 threaded on each of the posts [3 andurging the washers into surface contact with the insulating sheet 24. A second washer 21 is mounted upon each post 13 to: overlie the nuts- 26," and a relatively heavy weight 23 apertured at 29 to receive each of-the posts without contacting same-issuperimposed' on thewasher 21, the weight 28- being preferably formed of material having a low specific-heat coeflici'ent as described in connection with the pressure plate 22 A third-washer iid'and an additional nut 3! are positioned upon each of the posts l3 to overlie the weight 28 and to secure the same.-- I

The structure of the present invention, as hereinbefore described, makes possible the attainment of several advantages over the prior art constructions. First, the means for applying pressure to the heating element assembly l1, thus urging the assembly into eificient thermal relation with the sole plate ll facilitates the transmission of thermal energy from the heating assembly to the sole plate.

It will be noticed particularly from Figure 3 that the weight 28 is thermally insulatedfrom the heating assembly I! and the pressure plate 22 by both the insulating sheet material 24 and an air gap A. This air gap is substantially coextensive with both the longitudinally and transverse dimensions of the interior of'the cover IL- Thermal insulation is further facilitated by the pro-- vision of enlarged apertures in the heatingelement assembly H, the pressure plate 22, and the insulating sheet 24 so that each of these members 4 is out of direct physical contact with the posts 13. Thus, thermal insulation of the weight 28 aids in concentrating heat at the sole plate H and the heating element assembly I! superimposed thereon.

The use of a pressure plate 22v and a weight 2 8 made of a low specific heat material results in a significant decrease in the consumption of electrical energy by these members. Since less heat is necessary to raise these members to the temperature which they must assume in operation of the iron, a maximum amount of heat is available at the sole ll, thereby increasing the emciency of the iron.

As a result of the hereinbefore described featur'es-of the present invention, substantially all of the electrical thermal energy supplied by the heating element assembly I! is available over a relatively small portion of the complete iron, namely, at the sole plate II and at the pressure plate 22. This concentration of heat at the sole plateis facilitated by the employment of low specific heat material for the pressure plate and the-weight, pressure contact of the heating element with the sole plate, and the efiective thermal insulation of the weight by both the air gap A and'the insulation sheet 24-. It will of course be realized that a thermostatic control-may be employed in conjunction with the iron, as isconventional in the art, without necessitating. any material change in the structure and/or features hereinbefore described.

It will be understood that modifications and variationmay be efiected without departingfrom the scope of the novel concepts of the present invention.

I claim as my invention:

1. In an electric flat iron, a sheet metal sole plate, anupstanding post secured to saidsole plate, an electrical resistance heating element apertured to receive said post and in extended surface engagement with-said-sole plate, a pressure plate aperturedtoreceivesaid post and-in co-extensive surface engagement with said heatingelement, means on said post for urging said pressure plate toward-said sole'plate, therebyto press the heating element into intimate heat= exchange contact with the sole plate, a ballast weight carried by said post in spaced relation above-saidpressure plate, said pressure. plate and said ballast weight having specific heats substantiallylower than-saidsole plate, whereby the flow of wasted heat to the pressure plate and the ballast weightisminimized, and a sheet=of thermalinsulation material interposed in the space between'said weight and said pressure plate and orflsuch thickness as to leave an insulating. air space therebetween 2. In. an' electric fiat iron, a sheet-metal sole plate, an upstanding threaded studintegral withsaid sole plate,- a flat electrical resistance heating element aperturedtoreceive said. stud and in extended surface contact with said sole'platasa' pressure plate apertured to receive said stud without: contacting' same-and in (ac-extensive surface engagement with said heating --element;. a sheet of thermal insulation material coexte'nsively overlying saidpressure plate, means threaded on said" studand bearing against said insulatingishee't for urging said. pressure plate toward said sole ballast weightapertured to receive said stud without contacting same and carried by'saidthreaded vmeans in spaced relation from said insulating".

5' sheet to create an insulating air space between said sheet and said weight, said pressure plate and said ballast weight having specific heats substantially lowerthan said sole plate, whereby the flow of waste heat to the pressure plate and the 5 ballast weight is minimized.

JGSE ANTONIO GUERRA.

REFERENCES CITED The following references are of record .in the 10 file of this patent:

STATES F'A'IENTB Number Number Name Date Richardson r. Apr. 26, 1910 FOREIGN PATENTS Country Date Great Britain of 1945 France H-.- ot 1939 

